Transmission mechanism



Feb. 18, 1936. M. NATE. LA

TRANSMISSION MECHANISM Filed April 7, 1933 Patented Feb. 18, 1936 PATENTOFFICE 2,031,059 TRANSMISSION MECHANISM Matteo Natella, Salerno, ItalyApplication April 7, 1933, SerlalNo. 664,945

In Italy May 12, 1932 7 Claims. (can-331) My invention relates to powertransmitting mechanisms and particularly to mechanisms of this classsuch as are incorporated in automobiles and other motor driven vehicles.

The object of my invention is to provide a power transmitting mechanismfor connecting a prime power shaft with a driven shaft which willfunction automatically to vary the degree of power supplied to thedriven shaft according to variations in the load imposed by the latterupon said power transmitting mechanism. It is also an object of thisinvention to provide a mecha nism of the character described which canbe manually adjusted at will to vary the speed of the driven shaft.

To these ends I have provided an automatic power transmitting mechanismwhich operates automatically to vary the speed and power of the drivenshaft in accordance with variations in the load imposed thereby uponsaid mechanism and which, in its preferred form, also includes manuallyadjusted means for controlling the speed of the driven shaftr Otherfeatures of my invention are hereinafter pointed out.

In the accompanying drawing:

Figure 1 is.a plan view, partly in section and partly in elevation of apower transmitting mechanism constructed in accordance with my inven-Figure 2 is a detail hereinafter described.

Figure 3 is a plan view of one of the mutilated gears hereinafterdescribed.

Figure 4 is a section on line 4-4 of Figure 3.

Figure 5 is a section on line 55 of Figure 1..

Figure 6 is a section on line 6-6 of Figure 1.

t Figure 'I is a sectional detail of the free wheeling clutchhereinafter referred to.

Having reference to the drawing I represents the prime power shaft whichmay be the crank shaft of an internal combustion engine of a motorpropelled vehicle and 2 is a driven shaft axially alined opposite oneend of prime power shaft I. Driven shaft 2 is made with a trunnion 8loosely occupying a socket provided for it in the adjacent end of theprime power shaft I.

Intermediate its ends prime power. shaft I is made with a transversehearing within which is Journaled a transverse spindle 4 whose outer endportions are journaled within bearings provided within a ring 5. i

Spindle 4 has fast upon its outer end portion a beveled gear 6 meshingwith a crown gear 'I that is loosely mounted upon prime power shaft I.

The crown gear I is made in two parts which provide between them achamber within which is arranged a coiled spring 8-whose outer end isfastened to crown gear I and whose inner end is fastened to acylindrical sleeve 9 surrounding prime power shaft I and held againstendwise 5 movement relatively thereto by crown gear I with relation towhich, however, it is at times rotated. The hub of crown gear I isloosely journaled on the prime power shaft I, but is held against axialmovement thereon by shoulders provided-upon said shaft.

The sleeve 9 is formed upon itsinterior with spiral grooves which are inmesh with spiral ribs I0 provided upon a second sleeve II that isconnected' by straight longitudinal splines with prime power shaft I.The sleeve I I supports the sleeve 9 and is slidablysplined on primepower shaft I so that when it is moved axially on the latter it servesto rotate sleeve 9 relatively to prime power shaft I and gear 'I and sothat when I said sleeve II is rotating with prime power shaft I and atthe same time is held against axial movement thereon it transmits rotarymotion to sleeve 9 so that the latter rotates around the axis of shaft Iin unison with the bodily movement of gear 6 around said axis.

So long as the power stored up in spring 8 equals the load imposed uponthe mechanism by driven shaft 2, there is no relative movement betweenthe gears 6 and I. When, however, the load increases the gear 6 will lagor fall behind the crown gear I with the result that spindle 4 is turnedin one direction. So also when the load imposed by driven shaft 2decreases crown gear I will lag behind the gear 6 with the result thatspindle 4 will be turned in the opposite direction. Thus, so long as thetension of spring 8 equals the load there is no relative movementbetween gears 6 and I, but as this load varies the crown' gear 1 willmove ahead of, or fall behind, the gear 40 6 and ring 5 during theirmovement around the axis of prime power shaft I. Sleeve II extendsoutside of the sleeve 9 and is provided with a plurality of radially;disposed spring pressed bolts I2 whose inner ends co-operate withcircumferential grooves I3 formed'upon' the exterior of the prime powershaft I. The bolts I2 are provided at their outer ends with heads toco-operate with a conical sleeve I4 that is slidable axially on sleeve II. When sleeve I4 is manually shifted toward the right, Fig; 1, thebolts I2 are retracted against the pressure of their springs therebywithdrawing their inner ends from the-groove I3 occupied by them.It-will be clear that when the bolts I2 occupy their retracted positionsthe sleeve II may be moved longitudinally on prime power shaft I bymeans of a shipper member, not shown, engaging a groove I5 provided uponthe exterior thereof. It will also be clear that when the sleeve is thusadjusted the effective strength or tension of spring 8 is varied.

The conical sleeve I 4 is made with an outwardly extending flange to beengaged by a manually operated shipper member, not shown.

Surrounding the prime power shaft I and alongside of spindle 4 are fourcylindrical gear members IS, IT, I8 and I9 that are telescopicallyassociated with the innermost member I6 journaled loosely on prime powershaft I. In other words the outermost member I9 is rotatably supportedby member I8; the latter is rotatably supported by the member II; themember I1 is rotatably supported by the member I6, and the member I6 isrotatably supported by shaft I. The ends of these members adjacent tospindle 4 are formed each as a beveled gear 29, while the opposite endportion of each is formed as a spur gear 2I. The ends of the members I6,II, I8 and I9 which are nearest spindle 4 are radially alined. Themembers I6, I'I, I8 and I9 are of different lengths, the inner member I6being longest and the outer member I9 being .shortest with the resultthat the cylindrical gears 2I are of different diameters and stepped asshown in Figure 1.

Each gear 2I is continuously in mesh with one of the gears of a set ofstepped spur gears 2 2a, etc., fast on a counter shaft 23. Counter shaft23 is also a driven shaft of the mechanism and has fast on it afree-wheeling clutch member 24 through which rotary motion of shaft 23in one direction is transmitted to a second free-wheeling clutch member25 that is normally loosely mounted on counter shaft 23. Clutch member25 has a hub portion formed exteriorly with gear teeth 26 to mesh with agear 21 that is splined upon the driven shaft 2. The hub of gear 21 ismade with an annular groove 28 for engagement with a shipper member, notshown, by means of which gear 21 is adjusted axially on shaft 2 to moveit into and out of engagement with gear teeth 28 and also to throw themechanism into reverse. The means through which counter shaft 23 drivesshaft 2 in reverse comprises a gear 29 fast on shaft 23, and anintermediate gear 29a with which the gear 21 is meshed when shiftedtoward the right, Fig. 1, out of mesh with gear 26.

A manually operated clutch member 38 splined on shaft 23 is providedupon its exterior, and near one end thereof, with teeth 3| so that whenclutch member 39 is manually shifted toward the left, Fig. 1, itstoothed portion enters a toothed socket 32 provided within the hub ofclutch member .25

to lock the latter to counter shaft 23 thereby to suppress the freewheeling function of members 24 and 25.

When gear 21 is moved toward the right out of mesh with gear 26 it maybe brought into mesh with intermediate gear 29a on a small arbor, notshown, which gear 29a is always in mesh with the gear 29 on countershaft 23. Thus by shifting gear 2! toward the right as described, shaft2 will be driven in reverse.

The spindle 4 carries four beveled gear segments at, b, c and d eachdisposed opposite one of the beveled gears on drums IG-I 9, inclusive,in position to co-operate therewith.

As shown in Figures 1 and 2 the segments a, b and c are made,respectively, with pairs of gear teeth a. b and 0', while the segment (2is made with four gear teeth d. The teeth 12' are angularly offset inone direction with respect to the teeth a; the teeth 0' are angularlyoffset in the same direction with respect to the teeth b, and the groupof teeth d is angularly offset with respect to the teeth 0', all asshown in Figure 2.

As shown in Fig. 2 the first tooth of segment a is interlocked with theconical gear of sleeve I9 and as segment a is carried bodily aroundshaft I.

"while held against rotating on its own axis by spring 8 acting throughgear I, it acts to rotate cylinder I9, gear 22a and shaft 23, and thelatter acts through the free-wheeling clutch 24-25 to rotate gear 21 andthe driven shaft 2. So long as the load imposed by shaft 2 is no greaterthan the power of spring 8, the spindle 4 and segment a will swingaround the axis of shaft I without rotary motion on their own axes andwithout relative movement between crown gear I and shaft 1 or gear 6.

If the load imposed by shaft 2 becomes greater than the power of spring8, then the latter will yield and segment a will roll forwardly oncylinder I9 thereby rotating spindle 4 and gear 6 in a direction toadvance crown gear I relatively to shaft I with the result that thetension of spring 8 is increased until its resistance balances the.

load or until segment a rolls out of mesh with the teeth of drum I9. Ifthe partial rotation of segment a does not sufliciently increase thetension of spring 8 to overcome the resistance to rotation of drum I9and shafts 2 and 23, then segment a. will continue to roll on drum I9until its second tooth is in engagement'with said drum I9 therebyfurther increasing the tension of spring 8. If this increasedtension ofspring 8 is still insufficient to hold segment a against rotating on itsown axis the segment a will continue to roll on drum I 9 thereby actingthrough spindle 4 and gear 6 to advance crown gear I still further andfurther increasing the tension of spring 8. If the resistance of drum I9is still greater than the resistance of spring 8 the spindle 4 willcontinue to be rotated until the second tooth passes out of engagementwith drum I9 simultaneously with which the first tooth of segment bengages its drum I8 so that shaft 23 is driven through the parts I8 and22b.

During the operations just described the gear b is being turned on itsaxis with the gear a and when the latter disengages drum. I9 the firsttooth of gear b is in engagement with its drum I8.

It will thus be clear that thereafter if the tension of spring 8continues insufilcient to hold segment b against rolling forwardly onits drum I8 the segment b will roll on drum I8 thereby increasing thetension of the spring 8 until the power of said spring is equal to theload, or until segment bmoves out of engagement with drum I8 and segment0 into engagement with drum I1. If the tension of spring 9 continuesinsufficient to hold segment 0 against rolling forwardly on its drum I!said segment will roll forwardly on said drum II thereby furtherincreasing the tension of spring 8 until said segment 0' disengages drumI I and segment d has engaged'drum It.

Drum I6 is part of the lowest speed train of gearing through which shaftI drives shafts 23 and 2 and if the resistance of drum It to rotationexceeds the maximum increase in the power of spring 8 resulting throughthe engagement of segment d with drum I6, then sleeve ll can be adjustedinwardly to still further increase the occupied by a lug 35 forming partof the spindle 4, and the recess 34 is'of angular length sufllcienttopermit its gear to move relatively to spindle 4' to a limited extent.

Housed within a chamber 38 formed within each segment 4:, etc., belowits recess 34 is a coiled spring 31 which normally maintains one end ofrecess 34 against one side of its lug'35. When either beveled gear b, cor d is first brought into engagement with its drum the spring 31 yieldsand the rotation of said segment on the axis of spindle 4. is arrestedbecause of the yielding nature of spring 31, until the second tooth ofthe segment that is moving out of mesh with its drum clears the latter.

The spindle 4' serves as a fulcrum for a lever which when the mechanismis in operation, is

subjected to the influence of two opposed forces,

viz., the resistance offered by the load imposed by shafts 23 and 2 uponone arm of this lever and the tension or resistance of spring 8 actingthrough the crown gear upon the other arm. thereof. One arm of thislever is constituted, or represented, by the portion of the beveled geara, b, cor d that extends from the axis of spindle 4 to the tooth thereofthat is in engagement with one of the drums while the other arm isrepresented by the" portion of beveled gear 6 which extends from theaxis of spindle 4 to its point of engagement with crown gear 1.

The fulcrum and driving spindle 4 extends radially from the shaft I andbecause of its movement around the axis of the latter after the mannerof a crank arm acts through one arm of the lever just mentioned to drivethe driven shaft while the tension of spring 8 is imposed upon the otherarm of the lever in a direction to hold said lever against rotativedisplacement on the fulcrum 4.

As above described the eifective power of the mechanism as applied toshaft 23 or 2 is autowhen the load is at its minimum the drive is.

through the segment a and it would, therefore, be almost impossible togo at a low speed in roads where low speed is required because oftrafllc or for other reasons. In such cases the sleeve II is adjustedlongitudinally outwardly on prime power shaft I so as to reduce thestrength of spring 8 with the result that the drive is'automaticallyshifted from one segment on spindle 4 to the next until the strength ofspring 8 is reduced to a point where the speed of the vehicle is reducedto the desired point. This transfer of the drive from one segment a, bor c to the next in. order to reduce the speed of the vehicle isoccasioned by outward longitudinal adjustment of sleeve l I on shaft I.

It will be observed that shaft 2 can be driven at any one of four speedswhen the mechanism is set in reverse.

When segment d is driving its drum I8 the mechanism is in first speed;when segment c is driving itsdrum I! the mechanism is in second speed;when segment b is driving its drum l8 the mechanism is in third speed,and when segment ais driving its drum l8 the mechanism is in fourthspeed.

It will be observed that the free-wheeling devices 24 and 25 mayfunction for all four speeds of the mechanism. Also that this functioncan be suppressed by means of clutch member 38 when the mechanism isthrown into reverse.

Herein I have embodied my invention in a mechanism such as would beincorporated in an automobile in which case the shaft 2- is the drivenelement and is connected through the usual differential with the drivingwheels of the vehicle. However, insome forms of my invention the shaft2, gear 21, gear 28 and gear 29 may be dispensed with, in which case theshaft 23 is the driven element of the mechanism. I

When the above described transmission is operating under an unvaryingload one or the other of the segments a, etc., is in mesh with its druml6, l1, l8 or [9 and there is no relative movement between said twoparts, thesegment and its 'irum traveling as one around the axis of thedriving shaft I. It will be noted that when segment a is driving drum ISthe latter acts through It will also be observed that when segment b isthe driver its drum l8 acts through countershaft 23 to drive drum I 9 ata slower speed than drum l8 and drums l1 and I6 at greater speed thansaid drum l8. Thus while the mechanism is in operation all of the drumsare rotating but at different speeds. While traveling under an unvaryingload the spindle 4, swinging around the axis of shaft I after the mannerof a crank arm, carries with it the beveled gear 6 as well as thesegments and gear 1. Gear 6 and the drum or cylindrical gear that isthen functioning all rotate together around the axis of drive shaft I inunison as indicated by the arrows in Fig. 2 and there will. be norelative movement between those parts. -When, however, the load becomesgreater than the tension of the spring 8, the

movement of the drum will be retarded thereby rotating shaft 4 on itsaxis in a direction to advance gear 1 in the direction of the arrow,Fig. 2,

tion of a driving shaft; a driven shaft; a spindle carried by saiddriving shaft and disposed crosswise thereof; a plurality of segmentalbeveled gears mounted side by side on said spindle so as to swing aroundthe axis of said driving shaft; a plurality of telescopically associatedhollow drums that are concentrically disposed with relation to the axisof said driving shaft and each of which is made at one end with a bevelgear co-operatively disposed with respect to one of said segmentalbeveled gears and made at its opposite end with a spur gear, the spurgears of the several drums being of different diameters; a plurality ofspur gears fixed in position upon said driven shaft each of which iscontinuously in mesh with the spur gear of 'one of said drums, andautomatic means for operating said spindle so as to selectively controlthe engagement of said segmental beveled gears individually with the,beveled gears of said drums according to variations in the load imposedupon said mechanism by said driven shaft.

2. In a transmission mechanism, the combination of a driving shaft; adriven shaft; a spindle carried by said driving shaft and disposedradially thereof; a plurality of segmental beveled gears mounted side byside on said spindle so as to swing around the axis of said drivingshaft; a plurality of telescopically associated hollow drums that areconcentrically disposed with relation to the axis of said driving shaftand each of which is made at one end with a beveled gear cooperativelydisposed with respect to one of said beveled segmental gears and at itsopposite end with a spur gear, the spur gears of the several drums beingof different diameters; a plurality of spur gears fixed in position.upon said driven shaft each of which is continuously in mesh with thespur gear of one of said drums, a beveled gear fast on said spindle; abeveled gear loosely mounted on said driving shaft and engaging saidlast mentioned beveled gear, and a spring having one end thereofcooperatively associated with said driving shaft and its opposite endcooperatively associated with said loosely mounted gear so as toyieldinglyoppose rotary motion of said loosely mounted beveled gearrelatively to said driving shaft under the influence of an increase inthe load imposed upon' said loosely mounted gear by said driven shaft.

3. A transmission mechanism constructed in accordance with claim 2wherein manually operable means is provided for varying the power ofsaid spring thereby to control the speed of said .driven shaft.

4. A transmission mechanism having, in combination, a driving shaft; adriven'shaft. and mechanism through which power is transmitted from saidshaft to said driven shaft. said mechanism comprising a shaft 'rotatablysupported by said driving shaft and disposed radially with respect tothe axis of the latter, a plurality of gear segments spirally arrangedon said radial shaft at different distances from the axis of saiddriving shaft, a plurality of gear members for rotating said drivenshaft, each of said members being cooperatively associated with one ofsaid gear segments so that it is at times rotated thereby, and springmeans connecting said driving shaft with said radial shaft foryieldingly opposing rotative displacement in one direction 6 of saidradial shaft and its gear segments under the influence of a dominatingincrease in the load thereby to selectively control the action of thegear segments so as to equalize the effective force of said spring meansand the load, and for yield- 10 ingly urging said radial shaft and itsgear segments to turn in the opposite direction in response to adecrease in the load thereby to selectively control the action of thegear segments so as to equalize the effective force of said means andthe load.

5. A transmission mechanism constructed in accordance with claim 4, andincluding also manually operable means through which the power of saidspring means is varied to control the speed of said driven shaft.

6. A transmission mechanism constructed in accordance with claim 2wherein said spring is a coiled spring surrounding said driving shafthaving one of its ends fastened to said loosely mounted beveled gear andincluding also a sleeve rotatably supported within said coiled spring bysaid driving shaft and to which the opposite end of said spring isfastened, and means normally holding said sleeve against'rotationrelatively to said driving shaft, said means being manually operable torotatively adjust said sleeve relatively to said driving shaft.

'7. A transmission mechanism constructed in accordance with claim 1wherein each segmental beveled gear is connected with said spindle sothat it is rotatively movable thereon to a limited extent and wherein aspring is provided for holding each of said segmental beveled gears atthe limit of its rotary movement in one direction with respect to saidspindle.

iMA'I'TEO NATELLA.

